Crohn's disease and Mycobacterium avium subsp. paratuberculosis: current issues
1Microbial Food Safety Risk Assessment Unit, Laboratory for Foodborne Zoonoses, Health Canada, Guelph, Ontario. janet_harris@hc-sc.gc.ca
Abstract:
Crohn's disease is a chronic debilitating inflammatory bowel disease of unknown etiology. Proposed causes include bacterial or viral infection, diet or exposure to tobacco smoke, genetic abnormality, and immune dysfunction. The bacterium Mycobacterium avium subsp. paratuberculosis (Map) has received much research attention as a potential cause of the disease. Map causes Johne's disease in ruminants. The pathology of Johne's disease superficially resembles that of Crohn's disease in humans. Some researchers have shown evidence of Map in intestinal tissues of Crohn's disease patients. Studies are in progress to investigate the possibility that Map exists in milk from infected cows and survives pasteurization. This is a controversial subject with the potential for media attention and public outcry. We examined the current literature and concluded that insufficient evidence exists at this time to implicate any one factor, including Map in milk, as the definitive cause of Crohn's disease. The high degree of uncertainty in this issue requires regulators to recognize the need for effective risk communication as ongoing research provides additional information about the disease.
Insights
Current evidence does not definitively link Mycobacterium avium subsp. paratuberculosis (Map) to Crohn's disease. Further research is needed to understand potential causes of this inflammatory bowel disease.
Area of Science:
- Gastroenterology
- Microbiology
- Immunology
Background:
- Crohn's disease is a chronic inflammatory bowel disease with unknown causes.
- Potential etiologies include infections, genetics, diet, and immune dysfunction.
- Mycobacterium avium subsp. paratuberculosis (Map) is investigated as a potential cause due to similarities with Johne's disease in ruminants.
Purpose of the Study:
- To review the current literature on potential causes of Crohn's disease.
- To assess the evidence implicating Mycobacterium avium subsp. paratuberculosis (Map) in Crohn's disease etiology.
- To evaluate the role of Map in milk and its survival through pasteurization.
Main Methods:
- Literature review of existing studies on Crohn's disease and Map.
- Analysis of research findings on Map detection in human intestinal tissues.
- Examination of studies investigating Map in milk and pasteurization.
Main Results:
- Evidence remains insufficient to definitively identify Map or any single factor as the cause of Crohn's disease.
- Some studies suggest the presence of Map in Crohn's disease patients' intestinal tissues.
- The presence and survival of Map in milk and its link to Crohn's disease require further investigation.
Conclusions:
- No single factor, including Map in milk, is currently proven to be the definitive cause of Crohn's disease.
- Significant uncertainty surrounds the etiology of Crohn's disease.
- Effective risk communication is crucial as research progresses.
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